What is the DIA file format?
.DIA is the native diagram file format of the Dia diagram editor, a free, open-source vector drawing application from the GNOME ecosystem. It stores flowcharts, UML diagrams, entity-relationship models, network diagrams, and other technical drawings in a structured, editable form.
Internally, a .dia file is a gzip-compressed XML document. Decompressing it reveals a <dia:diagram> root element containing layers, objects (shapes and connectors), geometric coordinates, and per-object properties such as line color, fill, and text labels. The file begins with the standard gzip magic bytes 1F 8B 08. Dia can also save diagrams as plain (uncompressed) XML using the same .dia extension, in which case the file opens directly as readable XML. The gzip CRC-32 provides basic integrity checking for the compressed stream.
The format is open and documented under the dia: XML namespace. Dia was originally written by Alexander Larsson in 1998; the last stable release, Dia 0.97.2, appeared in December 2011. The file format has been stable across the 0.9x series and remains readable by current builds of the application.
Dia exports diagrams to SVG, PNG, PDF, EPS, DXF, and other formats, but the .dia file itself is the editable native source. For users migrating away from Dia, draw.io (diagrams.net) provides active development and can serve as a modern replacement, with manual import via exported SVG or XML.
Security & safety
RISK: LOWA .dia file is gzip-compressed XML describing a drawing - it contains no macros or executable code and is safe to open in Dia or draw.io. The only practical note: get Dia from the official GNOME/Dia site or your Linux distribution's repository, since third-party "Dia viewer" download portals can bundle adware. You can also rename a copy to .gz and decompress it to inspect the raw XML.
Format details
in a nutshell- Microsoft SharePoint Server 2007 temporary file - A transient server-side file SharePoint 2007 could create; not a user document and effectively obsolete - unrelated to the Dia diagram format.
- DESQview / generic data file - Rare legacy uses of the .dia extension exist; none are common today versus the Dia diagram.
Programs that open DIA files
Windows2 apps
Dia Diagram Editor
Open-source Install Dia for Windows, then File > Open the .dia file to view and edit it. 
draw.io Desktop (diagrams.net)
Open-source Use File > Import (Dia .dia import) to bring the diagram into draw.io for editing/export. 
macOS2 apps
Dia Diagram Editor
Open-source Install Dia (via the official build or Homebrew), then File > Open the .dia file.
draw.io Desktop (diagrams.net)
Open-source Import the .dia file (File > Import) to view and re-export it. 
Linux2 apps
Dia Diagram Editor
Open-source Install from your distro repo (e.g. 'sudo apt install dia'), then open the .dia file. Native platform for Dia.
draw.io Desktop (diagrams.net)
Open-source Import the .dia file to edit/export it without installing Dia.
diagrams.net (draw.io online)
Free In the browser choose File > Import from > Device and select the .dia file. Technical details
deep spec| File type | gzip-compressed XML vector diagram |
| Encoding | XML (UTF-8), gzip-compressed by default |
| Magic bytes | 1F 8B 08 (gzip signature) when compressed; plain XML begins with <?xml and <dia:diagram> root when stored uncompressed |
| Container | gzip stream wrapping a single UTF-8 XML document |
| Compression | gzip/DEFLATE applied to the whole XML document by default; can be disabled to store plain XML |
| Typical file size | 2 KB - 500 KB (compressed; most diagrams are small vector documents) |
| XML root element | <dia:diagram> with nested <dia:layer> and shape/connector object children |
| Coordinate system | Canvas measured in centimeters; vector-based, effectively unbounded canvas size |
| Integrity | gzip CRC-32 on the compressed stream (container-level integrity check) |
| MIME type | application/x-dia-diagram |
| Diagram types | Flowcharts, UML (class, sequence, state), ER diagrams, network diagrams, circuit diagrams (via shape plug-in libraries) |
| Export formats | SVG, PNG, PDF, EPS, DXF, WMF, CGM (from Dia application) |
| Format stability | Stable across Dia 0.9x series; backward compatible - files from Dia 0.90 open in Dia 0.97.2 |
| Released | 1998 (Dia diagram editor, part of the GNOME ecosystem) |
| Latest version | Dia file format as written by Dia 0.97.x (last stable, 2011); format stable since |
| Open standard | Yes · royalty-free |
| Specification | wiki.gnome.org |
DIA conversions
Community Q&A
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